The present invention relates to a revolutionary new type of bicycle invented by myself and disclosed and claimed in my copending U.S. patent application Ser. No. 266,181, filed May 22, 1981, now U.S. Pat. No. 4,669,747. Conventional bicycles comprise a rigid frame including a central post in which a seat is mounted, a top crossbar rigidly connected to the central post near the top thereof and extending forwardly to a front journal tube in which the separate front wheel frame, or fork, is rotatably journaled, and a bottom crossbar which extends upwardly and forwardly from the bottom of the center post, usually from the crank shaft hub mounted at the bottom of the central post, to the front journal hub at a point just below the top crossbar. The center post, top crossbar and bottom crossbar define the three legs of a rigid structural triangle.
In the revolutionary new bicycle of my invention, the foregoing rigid, triangular-shaped frame member is eliminated. I eliminate the bottom crossbar altogether and provide for a flexible spring connection between the top crossbar and the center post. One or more tension cables extend from the front portion of the frame, near the front of the top crossbar, downwardly to a point on the rear portion of the frame near the bottom of the center post. This construction is especially well adapted to dirt bike racing in that the frame itself is designed to absorb the shocks of rough riding. Further, when pedalling torque spreads the frame, the springs at the tension cable ends are compressed. At the end of the pedal stroke, the spring relaxes and drives the crank upward for an extra kick when the pedals are on the upstroke part of their travel.
One problem with this construction is that the front portion of the frame and the front wheel tend to yaw laterally from side to side relative to the rear frame portion as the bicycler pedals. Heretofore, I have solved this problem by using a wider flat spring at the junction between the crossbar and the center post. While this solution has been somewhat satisfactory, it has not eliminated the yawing action completely and it makes the bicycle less attractive due to the appearance of the relatively wide flat spring and the flat spring housings.